• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.3
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• pp.137-149
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• 2021

Cable-stayed bridges are infrastructure facilities of a highly public nature; therefore, it is essential to ensure operational safety and prompt response in the event of a collapse or damage caused by natural and social disasters. Among social disasters, impact accidents can occur in bridges when a vehicle collides with a pier or when crashes occur due to aircraft defects. In the case of offshore bridges, ship collisions will occur at the bottom of the pylon. In this research, a procedure to evaluate the structural behavior of a cable-stayed bridge for aircraft impact is suggested based on a numerical analysis approach, and the feasibility of the procedure is demonstrated by performing an example assessment. The suggested procedure includes 1) setting up suitable aircraft impact hazard scenarios, 2) structural modeling considering the complex behavior mechanisms of cable-stayed bridges, and 3) structural behavior evaluation of cable-stayed bridges using numerical impact simulation. It was observed that the scenario set in this study did not significantly affect the target bridge. However, if impact analysis is performed through various scenarios in the future, the load position and critical load level to cause serious damage to the bridge could be identified. The scenario-based assessment process employed in this study is expected to facilitate the evaluation of bridge structures under aircraft impact in both existing bridges and future designs.

• Journal of the Korean Geosynthetics Society
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• v.19 no.4
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• pp.41-50
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• 2020

Since cracks in concrete structures expedite corrosion of reinforced concrete over a long period of time, regular on-site inspections are essential to ensure structural usability and prevent degradation. Most of the safety inspections of facilities rely on visual inspection with naked eye, so cost and time consuming are severe, and the reliability of results differs depending on the inspector. In this study, a portable measuring device that can be used for safety diagnosis and maintenance was developed as a device that measures the width and length of concrete cracks through image analysis of cracks photographed with a camera. This device captures the cracks found within a close distance (3 m), and accurately calculates the unit pixel size by laser distance measurement, and automatically calculates the crack length and width with the image processing algorithm developed in this study. In measurement results using the crack image applied to the experiment, the measurement of the length of a 0.3 mm crack within a distance of 3 m was possible with a range of about 10% error. The crack width showed a tendency to be overestimated by detecting surrounding pixels due to vibration and blurring effect during the binarization process, but it could be effectively corrected by applying the crack width reduction function.

• Clean Technology
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• v.26 no.4
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• pp.293-303
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• 2020

According to the World Health Organization (WHO), air pollution is a typical health hazard, resulting in about 7 million premature deaths each year. Sulfur dioxide (SO2) is one of the major air pollutants, and the combustion process with sulfur-containing fuels generates it. Measuring SO2 generation in large combustion environments in real time and optimizing reduction facilities based on measured values are necessary to reduce the compound's presence. This paper describes the concentration measurement for SO2, a particulate matter precursor, using a wavelength modulation spectroscopy (WMS) of tunable diode laser absorption spectroscopy (TDLAS). This study employed a quantum cascade laser operating at 7.6 ㎛ as a light source. It demonstrated concentration measurement possibility using 64 multi-absorption lines between 7623.7 and 7626.0 nm. The experiments were conducted in a multi-pass cell with a total path length of 28 and 76 m at 1 atm, 296 K. The SO2 concentration was tested in two types: high concentration (1000 to 5000 ppm) and low concentration (10 ppm or less). Additionally, the effect of H2O interference in the atmosphere on the measurement of SO2 was confirmed by N2 purging the laser's path. The detection limit for SO2 was 3 ppm, and results were compared with the electronic chemical sensor and nondispersive infrared (NDIR) sensor.

• Journal of Convergence for Information Technology
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• v.12 no.1
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• pp.76-82
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• 2022

Recently, natural and social disasters in Korea are increasing, and new disasters such as COVID 19 and sinkholes, and large-scale disasters that combine natural and social disasters are occurring frequently. In order to reduce damage caused by disasters and effectively respond to disasters, the importance of disaster safety education is emerging because it is necessary to understand the awareness of disaster situations and the functional response process. Ministry of Public Interior and Security is providing disaster safety education for emergency managers through 54 specialized disaster safety education institutions. There is also a lack of experience facilities. This has a problem in that it makes it difficult for disaster safety personnel to effectively respond to disasters due to lack of experience in actual disaster sites. Also, unlike other education fields, the connection between disaster safety education contents and new technologies such as AI is still lacking. In this study, focusing on natural disaster, the current status and problems of domestic disaster safety education institutions and their contents are investigated and analyzed, and based on this, this study suggested improvement plans for domestic disaster safety education contents such as establishment of a unified disaster safety standard curriculum, production and distribution of disaster safety education experience contents using virtual reality technology and infotainment technology, and development of mobile AI tutoring service.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.153-160
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• 2022

This study presents the bogie arrangement of the load-out system for on-ground shipbuilding. The load-out system is one of the most important systems to perform the bogie arrangement of the on-ground shipbuilding technique without dry dock facilities, and this system is composed of four pieces of equipment: bogies, driving bogie with motors, trestles, and power packs. Also, the bogie arrangement analysis (BAA) is employed to simply calculate the reaction forces at the trestle for structural safety. In this context, the purpose of this study is to propose an optimal design method to perform the bogie arrangement satisfying structural safety requirements with minimal cost. It is expected that the proposed methodology will contribute to the effective practice as well as to the improvement of competitive capability for shipbuilding companies at the on-ground shipbuilding stage. Furthermore, we describe some problems and their solutions of the deformation that may occur in the bottom of the hull during the load-out process. As a result, it is shown that we applied it to the 114K crude oil tanker (Minimum bogie 54EA) and the 174K CBM LNG carrier (Minimum bogie 88EA), it can minimize the number of bogie and critical risks (Safety rate 1.61) during the load-out of on-ground shipbuilding. Through this study, the reader will be able to learn successful load-out operation and economic shipbuilding in the future.

• Korean Journal of Construction Engineering and Management
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• v.23 no.1
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• pp.46-53
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• 2022

The railway platform is an important facility closely related to the safety of passengers, trains, and images of railway facilities, and requires thorough facility management. However, the problem that the finishing material (plastering mortar) for the joint finishing of dissimilar materials (concrete+granite) falls off in the direction of the track at the platform podium is occurring multiple times across the country. Since these problems threaten the safety of train operation and the safety of passengers, immediate and continuous management is required. This study tried to derive improvement plans through the analysis of the drop-off problem of finishing materials occurring at the platform podium. The status of missing finishing materials for the platform podiums of about 200 railway stations and the related design and construction standards of the Korea National Railway were investigated. After that, the cause of the drop-off of the finishing material was analyzed, and as a result, it was found that the main cause was the boundary between the roadbed and the architectural process that occurred during construction. Subsequently, in connection with the derived causes and design, construction standards, (1) improvement of finishing materials or construction methods, (2) design of finishing materials that are easy to adjust height, (3) design of separate finishing methods, (4) improvement methods and durability were suggested.

• Journal of Korea Entertainment Industry Association
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• v.15 no.4
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• pp.73-87
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• 2021

Special theaters were created to provide a sense of immersion and spectacles due to differentiated screens, sound, seating facilities, and advanced services, and also expanded screens. The purpose of this study is to perform comparative analysis of the technical characteristics formats shown in special theaters(3D film, 4DX, IMAX, ScreenX, and VR) in order to identify and find ways to overcome the technological limitations in production. The various formats show differences in field of view depending on the exhibition technology and these differences affect the mise-en-scene, narrative, and editing of the film and consequently result in changes in the production environment and process. Therefore, directors and creators must understand the technological features and limitations of the new formats before making their approach. However, a new format encounters limitations on production sets due to the decline of technical education and succession. In situations where shooting with a special camera is essential, the particular characteristics of each format should be carefully considered from the planning stage but financial problems arise due to increase in production period and cost. To overcome these various obstacles, it is essential to first identify problems and present alternatives through in-depth research on the production set of each format. Finally, this research aims to explore the prototype of each format and analyze the current state of production technology with formats that have not been adapted to the market trends by combining with the other formats and showing that they can survive in new ways.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.991-1005
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• 2022

Satellite imaging is an effective supplementary data source for detecting and verifying nuclear activity. It is also highly beneficial in regions with limited access and information, such as nuclear installations. Time series analysis, in particular, can identify the process of preparing for the conduction of a nuclear experiment, such as relocating equipment or changing facilities. Differences in the semantic segmentation findings of time series photos were employed in this work to detect changes in meaningful items connected to nuclear activity. Building, road, and small object datasets made of KOMPSAT 3/3A photos given by AIHub were used to train deep learning models such as U-Net, PSPNet, and Attention U-Net. To pick relevant models for targets, many model parameters were adjusted. The final change detection was carried out by including object information into the first change detection, which was obtained as the difference in semantic segmentation findings. The experiment findings demonstrated that the suggested approach could effectively identify altered pixels. Although the suggested approach is dependent on the accuracy of semantic segmentation findings, it is envisaged that as the dataset for the region of interest grows in the future, so will the relevant scope of the proposed method.

• The Korean Society of Law and Medicine
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• v.23 no.3
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• pp.47-87
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• 2022

Due to the COVID-19 pandemic, non-face-to-face treatment was temporarily permitted. A lot of consensus has been formed on the need to continuous non-face-to-face treatment. However, the current 「Medical Service Act」 only permits telemedicine between doctors and medical personnel. On the other hand, as a result of legal interpretation, there is an opinion that non-face-to-face treatment is allowed. But considering the overall legal system, non-face-to-face treatment is not allowed. Nevertheless, we have to consider the reality such as the development of science and technology and the outbreak of infectious diseases. Therefore, it is not advisable to allow face-to-face treatment only. Ultimately, it is necessary to find ways to ensure that non-foce-to-face treatment can be performed in a safe and effective manner. And it should be institutionalized. This is strategically necessary and important. Therefore, we must look over ahead legal issues to be discussed. First of all, the scope, the target disease and the subject of implement have to be clear. Also, structurally, the standards of facilities and equipment must be prepared for non-face-to-face treatment to be implemented. Functionally, communication and information exchange between doctors and patients should be well conducted. In addition, the information protection management system that occurs in the process of non-face-to-face treatment should be materialized. Lastly, the issue of responsibility and cost of non-face-to-face treatment should be decided in detail. When these problems materialize, it can be expected that a safe non-face-to-face treatment environment will be established.

• Journal of Korea Port Economic Association
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• v.37 no.3
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• pp.93-104
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• 2021

A coastal ferries, which serve as a mode between mainland and offshore islands, are frequently used by islanders and travelers visiting islands. Therefore, it is located in a place with good accessibility to the downtown so that users can use it conveniently. However, research on the built environment and walking environment of coastal ferry terminals has not been conducted to ensure that elderly islanders and general travelers can use comfortably the coastal ferry terminal. In this study, with a focus on the coastal ferry terminal space, the walking section was set as 1)the accessibility of the coastal ferry terminal, 2)the built environment for using the coastal ferry terminal, and 3)walking environment in the ferry boarding and disembarkation at the coastal ferry terminal, and 4, 5)walking environment in the ferry. An evaluation tool was developed to measure the walking environment for each walking section, and the importance and satisfaction of users were analyzed using the IPA for the Yeosu Coastal Ferry Terminal. As a result, in the process of approaching the ferry terminal, 'convenience of using public transportation by foot' and 'convenience of using signposts guiding the location and direction of the ferry terminal' were investigated as concentrated areas. On the other hand, the built environment inside the ferry terminal and the walking environment showed that the satisfaction of the users was high. Regarding the walking environment from the ferry terminal to the ferry, the 'surface walking environment of the walking path', 'convenience of walking with luggage', 'convenience of walking in the slope section', and 'convenience of walking in the ferry ramp section' showed low satisfaction. This study can be used as basic data for improving the facilities and walking environment of Yeosu Coastal Ferry Terminal and is expected to be used as data for comparative research with other coastal ferry terminals.